Copper-base alloy



Patented Apr. 6, 1943 UNITED STATES PATENT OFFICE oorrEn-msn annoy Reginald 8. Dean and Garence '1. Anderson, Salt Lake City, Utah, assignors to Chicago Development Company, Chicago, 11]., a corporation of Illinois No Drawing. Application October 1, 1941, Serial No. 413,160

5 Claims.

Our invention relates to the preparation of alloys having good corrosion resistance under atmospheric conditions.

The alloys to which our invention relates are copper-base alloys containing from about 2% to about 25% manganese, from about 2% to about 20% chromium, from about 2% to about 25% iron, balance substantially all copper. Preferably, the alloys of our invention contain from about 70% to about 90% copper, balance consist- 10 slow cooled.

Hardness Corrosion test Corrosion test Hardness Coefficient of No. Comp. 0. W. Q450 C. Q550 C. Q650 C. ReSiStlVlty 107 NaCl H,s0,

as cast .251 intei mittent intermittent 1 Mn 2.5 Ho 46 Re 15 Re 19 Re -17 Re 32 14.74X10 C. W. 17 OXlO- Slight rusting Pickle only.

Or 2.5 S. C. 900 0.10.2)(10- Cu 90 Fe 5 2 Mn 2.5 Rc 42 Re 7 Re -l2 Rc l6 Re 24 1380x10 C. W. 18.4)(10- Darkening of Pickle only.

Cr 2.5 S. 0. 900 C. l0.8X10- surface. On 85 Fe 10 3 Mn 5 Bo -42 Re 1 Re 9 Re 10 Re --25 14.16Xl- C. W. 2-i.7) 10- Darkening of Pickle only.

Or S. 0. 900 C. 19.4Xi0-. surface. Cu 85 Fe 5 4 Mn 5 Re 27 Re 0 Re ---3 Re -6 Re 25 13.38X- C. W. 31.6)(10- Darkening of Pickle only.

Cr 5 S. 0. 900 C. 25.4 l0- surface. On 80 Fe 10 5 Mn 2 5 Re 32 Re +1 Re 5 Re 5 Re 19 13.74X10- C. W. 22.0X Rusted at sur- Pickle only.

Cr 2.5 S. 0. 900 C l5.l l0- face cracks. Cu 80 Fe 6 Mn 2 5 Rc 24 Re +3 Re 0 Re ---7 Be 22 1230x10 C. W. 22.7X10- Heavy rust- Pickle only.

Cr 2.5 B 0. 900 C 14.6)(10- ing of sur- Gu 75 face. Fe

7 Mn 5 R0 27 Re +2 Re -3 Re 8 Re 22 13.05x10- C. W. 29.6)(10- Darkening of Pickle only.

Cr 5 S. C. 900' C. 22.3X10- surface. On 75 Fe 15 8 Mn 7 5 Re 26 Re +4 Rc +2 Re 3 Re 20 1272x10 C. W. 37 8 l0- Darkening of Pickle only.

Or 7.5 S. 0. 900 C. 3l.6Xl0- surface. Cu 75 Fe 10 9 Mn 10 Re 24 Re +11 Rc +7 Rc +1 Re 13 13.40X10- C. W. 44 l 10- Darkening of Pickle only.

Cr 10 S. 0. 900 C. 38.2)(10- surface. Cu 75 Fe 5 V 10 Mn 2 5 Re 12 Re +1 Rc +4 Re 2 Re l6 12.30X-10- C. W. 24.4Xl0- Heavy rust- Pickle only.

Cr 2.5 1 S. 0. 900 C. 15 840(10- ing of sur- Cu 70 face. Fe 11 Mn 5 Re 24 Re +3 Re 1 Re 6 Re 22 12.54X10- C W. 324x Slight rusting Pickle only.

Cr' 5 S 0. 900 C 25 2x10 at small Cu s u r i a c e Fe 20 cracks.

12 Mn 7 5 Re 22 Re +9 Rc +2 Re 1 Re 12 13.71Xl0- O. W. 461x10 Slight rusting Pickle only.

Cr 7.5 S 0. 900 C 42 3X10- at small Cu 70 s u r f a c e Fe 15 cracks.

13 Mn 10 Re ---21 Be +7 Re 1 Re 0 Re 23 12.75xl0- C. W. 39.5X Darkening of Pickle only.

Cr 10 B. 0. 900 C. 32 9 1IH surface. Cu 70 Fe 10 14' Mn 12.5 Re 19 Re +11 Rc +11 Rc +1 Re 9 1271x10 O. W. 65.0X Darkening of Pickle only.

Cr 12.5 S 0. 900 0. 495x10 surface. On 70 Fe 5 content is approximately 2.5%.

Alloy No. 3, for example, listed in the above table, made from highly pure metals such as are obtained by electrolytic refining, is highly ductile and may be rolled into sheets or drawn into a wire or a rod. when such sheet, wire or rod is annealed at a temperature of about 750 degrees C., it has a tensile strength of approximately 45,000 pounds per square inch. On cold working, a tensile strength of about 75,000 pounds per square inch may be obtained. By intermediate amounts of rolling or by annealing at temperatures below 650 degrees 0., any desired intermediate degree of hardness may be obtained. The modulus of elasticity of the alloy is 22 10 pounds per square inch. The alloy shows only a slight darkening in an extended alternate immersion test in a 10% sodium chloridesolution, and is not attacked in a sul-' phuric acid solution.

All of the alloys of our invention possess fairly good resistance to atmospheric corrosion. Those of the alloys which contain more than 1.5% iron, however, undergo some rusting by extended alternate immersion in sodium chloride solution. Slight rusting also occurs with alloys containing a low as 5% iron where the manganese This rusting, however, in connection with the latter alloy, is completely overcome by the employment of 5% manganese and 5% chromium.. The preferred embodiments of our invention, therefore, where alloys are desired which are resistant to corrosion in salt water, encompass alloys containing trout about 5% to about manganese, from about 5% to about 15% chromium, from about 5% to about 15% iron, balance substantially all copper.

In the above table, it will be noted that we have expressed the hardness of the alloys, in various conditions, on the Rockwell (3 scale. For the purpose of correlating the hardness with the tensile strength, it may be pointed out that a hardness of Rockwell C 30 corresponds to a tensile strength or" approximately @5000 pounds per square inch, a hardness of Rockwell C zero cor responds to a tensile strength of approximately "15,000 pounds per square inch, and a hardness of Rockwell C 10 corresponds to a tensile strength of approximately 95,000 pounds per square inch. On this basis, it will be seen that an alloy con= taining 75% copper, 10% manganese, 10% chromium, and 5% iron (No. 9 of the above table) may be cold rolled to produce an alloy having a tensile strength of 95,000 pounds per square inch. The electrical resistance of such an alloy is 44.1 x 10- ohms/cmfi.

While the alloys of our invention have, generally speaking, many properties similar to those of nickel silvers, they have, in addition, certain advantages over nickel silvers in that, among other 5 things, many of them possess a wider range of work hardening properties as well as a wider range of electrical resistance.

As we have indicated hereinabove, we prefer to employ highly pure metals in the preparation of 10 the alloys 01 our present invention. We prefer,

particularly, to utilize metals produced electrolytically. In the case of manganese, for best results the said metal should have a purity of at least 99.0%, electrolytic manganese of a purity of 99.9% being especially satisfactory.

In the light of the various properties oi the alloys which have been described hereinabove, it will be apparent to those versed in the art that the said alloys may be utilized in various ways and for various purposes in the industrial and engineering fields. Illustrative uses of the alloys of our invention are for the preparation of springs, ratchets, pawls, electrical resistance wire, condenser tubes and other equipment re- 25 quiring resistance to corrosion by steam, decorative articles, and for other purposes to which nickel silvers, monel metal, and other alloys having a high nickel content are usually put.

What we claim as new and desire to protect by so Letters Patent of the United States is:

1. Alloys, having good corrosion resisting properties, containing about 2% to about 25% manganese, about 2% to about chromium, about 2% to about iron, balance substantially all copper.

2. Alloys, having good resistance to corrosion,

containing about 5% to about 15% manganese, about 5% to about 15% chromium, about 5% to about 15% iron, balance substantially all copper.

3. Alloys having good corrosion resisting prop erties containing about 2% to about 25% manganese, about 2% to about 20% chromium, about 2% to about 25% iron, balance copper, the copper constituting from 70% to 90% of the alloys.

4. Alloys, having good corrosion resisting properties, containing about 2% to about 25% e1ectrolytic manganese having a purity of at least 99.9%, about 2% to about 20% chromium, about 5% to about 15% iron, balance substantially all copper.

5. Alloys, having good resistance to corrosion, containing about 5% to about 10% manganese, about 5% to about 10% chromium, about 5% to about 10% iron, balance substantially all copper.

REGINALD S. DEAN.

CLARENCE T. ANDERSON. 

